OVERVIEW OF RESPIRATORY SYSTEM

I. Upper respiratory tract:

Fx:

1. Filtering of air

2. Warming & moistening

3. Humidification

1. Nose – cartilage

- Parts: Rt nostril separated by septum

Lt nostril

- Consists of anastomosis of capillaries –

Kessel – Bach Plexus – site of epistaxis

b. Pharynx (throat) – muscular passageway for air& food

Branches:

1. Oropharynx

2. Nasopharynx

3. Layngopharynx

c. Larynx – voice box

Fx:

1. For phonation
2. Cough reflex

Glottis – opening

Opens to allow passage of air

Closes to allow passage of food

II. Lower Rt – Fx for gas exchange

1. Trachea – windpipe

- has cartillagenous rings

- site for permanent/ artificial a/w – tracheostomy

b. Bronchus – R & L main bronchus

c. Lungs – R – 3 lobes = 10 segments

L – 2 lobes – 8 segments

Post pneumonectomy - position affected side to promote expansion of lungs

Post segmental lobectomy – position unaffected side to promote drainage

Lungs – covered by pleural cavity, parietal lobe & visceral lobe

Alveoli – acinar cells

- site of gas exchange (O2 & CO2)

- diffusion: Daltons law of partial pressure of gases

Ventilation – movement of air in & out of lungs

Respiration – movement of air into cells

Type II cells of alveoli – secrets surfactant

Surfactant - decrease surface tension of alveoli

Lecithin & spinogometer

L/S ratio 2:1 – indicator of lung maturity